Section-insulator and lightning-arrester for electric railroads



2 Sheets$heet' 1.

(No Model.)

B. THOMSON. SECTION INSULATOR AND LIGHTNING ARRESTER FOR ELECTRICRAILROADS.

No 463,761 Patented Nov. 24, 1891.

WITNESSEi (No Model.) v 2 Sheets-Sheet 2.

E. THOMSON. SEGTION INSULATOR AND LIGHTNING'ARRESTER POR- ELEGTRIGRAILROADS.

No. 463,761. Patented Nov. 24, 1891.

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m: nonms PEYERS co PHUY railway service.

NITTED STATES PATENT OFFICE.

ELIIIU THOMSON, OF SXVAMPSOOTT, MASSACHUSETTS.

SECTION-INSULATOR AND LIGHTNING-ARRESTER FOR ELECTRIC RAILROADS.

SPECIFICATION forming part of Letters Patent No. 463,761, dated November24, 1891.

Application filed September 1, 1890- Serial No. 363,680- (No model.)

To aZZ whom, it may concern:

Be it known that I, ELII-IU THoMsoN,a citizen of the United States,residing at Swampscott, county of Essex, and State of Massachusetts,have invented a new and useful Improvement in Section-Insulators andLightning-Arresters for Electric Railways, of which the following is aspecification.

The object of my present invention is to provide a practicablearrangement for interrupting electrically the trolley-wire of anelectric railway into insulated sections, each supplied with currentindependently by suitable feeders, while preserving the path of travelfor the contact-wheel unbroken,in order that leakages of current mayaffect only that particular section upon which the leak exists. Thesection-insulating device provided for this purpose may be connected toground in a way hereinafter described, and serve also as alightning-a-rrester. view I attach to but insulate from adjacentsections of the trolley-wire a series of conducting plates or surfacesseparated from one another by intervening insulation. These plates forma continuation of the line of the trolley-wire, and hence do notobstruct or interfere in any way with the passage of the trolley-wheel.The number of plates and intervening insulation-spaces will be soproportioned to the potential of the current upon the line that an arccannot be formed throughout the entire series, the principle on whichthis invention is based being the same as that set forth in myapplication for Letters Patent Serial No. 352,507, filed May 20, 1890.

In the accompanying drawings, Figure 1 is a perspective view showing theinvention applied to a single trolley-wire. Fig. 2 is a part side andpart sectional view of the sectional insulator. Figs. 3, 4t, and 5 aredetails illustrating the construction of the conductingplates.

The trolley-wire may be supported over the street by posts and guy-wiresorin any other of,the ways now known, and it is divided electricallyinto several sections at convenient points, two such sections beingshown at T T, which will be supplied independently wit-h current from afeed wire or wires'in the manner customarily employed in electric- Inorder to insulate these WVith this object in sections one from the otherI attach to them i a number of conducting plates or surfaces P,

separated from one another by intervening insulation and arranged inline with the trolley-wire, as shown in Fig. 2. It will of course beunderstood that the arrangement of these conducting-plates and the meansofattaching them to the trolley-wire may be va ried in a great manyways; but I prefer to thread the different plates upon a bolt B, coveredby an insulating tube or sheath B throughout its entire length, the boltpassing through central openings S in the plates. (Seen in Fig. 3.)Insulating-washerst 2' 2', preferably of mica or other non-inflammablematerial, space the plates the desired distance apart and prevent anydirect electrical connection from one to another. The bolt B connectsmechanically the two clamping ears or fins E E, each provided with anopening into which the bent ends of the trolley-wire are inserted andfastened byset-screws K K, and insulating-washers placed under nut 13and the head of bolt B guard effectively against electricalcommunication being established between the fins through the bolt. Thesewashers may be screw-threaded, and insulating-caps O G inclose the endsof the bolts to prevent the entrance of moisture thereto, the fins beingcut away to receive the caps. The conducting-plates andinsulating-washers are also perforated, as at R, Fig. 3, and throughthem is passed a pin or rod W, which will either be of insulatingmaterial or be insulated from the plates and ears and which holds theparts in place. Over the whole will be arranged a hood M, (partly shownin Fig. 2,) of insulating material, such as vulcanized fiber well oiledor painted, so as to shed moisture.

The conducting-plates are insulated at their upper ends by the washersand insulating sheath-covering bolt B; but at their contactends it isdesirable to have them entirely separated, mechanically as well aselectrically, with only an air-space between, so that moisture 0rmetal-dust cannot collect between the conducting-pieces, destroying theefficiency of the device.

Whenit is desired to make use of these section-insulators aslightning-arresters, or when leakage from one section to the other is tobe absolutely out off, one or more of the conducting-plates will beprovided with a ground connection. (Seen at L in Fig. 1.) For thispurpose an ear may be formed on the plate or segment, as ate, Fig. 4, toreceive the ground-wire leading therefrom. The earth connection willordinarily be made from the middle plate of the series, and then currentfrom either section will be intercepte at this middle plate and carriedto ground rat 1er than pass across the entire series of plates, as itmust do to get from one section to another. Lightning discharges alsoreach ground by jumping the insulating-spaces between the plates untilthe middle plate is reached, where they will pass to earth.

I make no broad claims herein for the invention of the divided are, asthis has been claimed in other applications of mine, particularly SerialNo. 352,507, already referred to.

That I claim as new, and desire to secure by Letters Patent, is

1. A section-insulator for insulating adja cent sections of anelectric-railway line conductor, comp rising separate conducting-platessecured in place, but spaced apart and insulated at points somewhatabove their contactsurfaces and having such contact-surfaces separatedentirely from one another by an airinsulation space, but rounded andarranged in line to form a continuation of the path of travel of thecontact device.

2. The combination of the clamping-ears connected with the adjacent endsof a sectional line conductor forelectric railways,with a boltconnecting said ears mechanically and a series of conducting-platesseparated by intermediate insulation supported upon but insulated fromsaid bolt and with their contact ends arranged in the path of travel ofthe contact device.

3. The combination of the bolt 13 between adjacent sections of anelectric-railway line conductor and insulated therefrom, with theconducting-plates arranged side by side upon the same in the path oftravel of the contact device, but insulated from thebolt, and thewashers of insulating material between the plates, as described.

4. The combination of the adjacent sections of an electric railway lineconductor and clamping-ears connected therewith,with the insulated boltjoining said ears, the conductin'g-plates thereon, the intermediatewashers of non-in flammable material, and the holding-pin V, asdescribed.

5. The combination of an insulating device connected with anelectric-railway line conductor for-insulating adjacent sections of thesame from oneanother and comprising a series of conducting-surfacesseparated from one another by intervening insulation, with a groundconnection leading from one or more of the plates at or near themiddleof the series, as described.

' EL'IHU THOMSON.

WVitnesses:

J OHN W. GIBBONEY, FRANK R. HILL.

